In 2013 ISO/TC 207/SC 1conducted a survey on ISO 14001 and ISO 14004 covering a range of potential areas for continual improvement. The survey results were published in February 2014 and are published in four parts:
Executive Summary [pdf,362kB]
Final report and analysis [pdf,549kB]
Survey design [pdf,208kB]
Supplemental results [pdf, 1.65MB]
The reports may be copied in part or in full, with the source quoted as ISO 14001 Continual Improvement Survey 2013, and reference to the SC1 web page www.iso.org/tc207/sc1.